It is found that the infection rate and infection degree of Paragonimus sinensis larvae metacercaria in live crabs are very high. Paragonimus sinensis parasitizes in the lungs, stimulates or destroys lung tissue, and can cause cough and even hemoptysis. If it invades the brain, it will cause paralysis. According to experts' investigation, the infection rate of paragonimiasis is 20% after eating crabs slightly, 55% when eating pickled crabs and drunken crabs, and 7 1% when eating crabs raw. The resistance of paragonimiasis metacercariae is very strong, and it usually takes 30 minutes in water at 55℃ or 48 hours in 20% salt water to kill it. If you eat crabs raw, you may be infected by Vibrio parahaemolyticus. When Vibrio parahaemolyticus invades the human body in large quantities, infectious poisoning will occur, showing symptoms such as intestinal inflammation, edema and congestion.